THIS invention relates to a header for a combine harvester.
Typical examples of known combine harvester headers are described in the specifications of South African patents ZA 84/8164, ZA 93/3794, ZA 95/9635 and ZA 95/10767. The headers described in these documents incorporate a series of individual reapers each of which has one or two augers located in a chute the base of which slopes upwardly to the rear and which is defined between upstanding side walls. A slot is formed in the base of the chute, beneath the auger(s), to receive crop stalks as the header moves through the land. The stalks are guided into the slot by forwardly tapered gathering shoes which project in front of the auger(s) on either side of the slot.
Known headers as described in the prior art documents referred to above suffer from a number of disadvantages, including the following:
As a further consequence, the use of a three-reaper configuration limits the harvesting operation to the harvesting of only three rows on each pass. However modern combine harvesters generally have a very large capacity, so that the harvesting of only three rows at a time results in considerable under-utilisation of that capacity. A further, resulting problem arises where the xe2x80x9cgroupsxe2x80x9d of rows, i.e. the groups of rows which the farmer can plant using a given planter, may not be uniformly spaced from one another. This further increases the difficulty of correcting harvesting the rows with conventional, fixed row-width headers.
As another example it is considered efficient in the case of irrigated maize to plant at a row spacing of 450 mm. However because there is no currently available header having reapers capable of handling this row spacing farmers will generally plant at a 900 mm row spacing. This row spacing can be handled by existing headers, but only after considerable adjustment and possibly even the addition of extra reapers. Apart from the reduction in land productivity resulting from the excessive row spacing, such adjustment and/or addition is time-consuming and inefficient.
The crop-receiving slots of the known headers are located substantially directly beneath the auger(s). Thus the stalks which enter the slots are positively engaged and pulled along the slots by the auger(s). For a given auger rotational speed, excessive ground speed of the combine harvester means that the auger(s) cannot pull the stalks along the slots fast enough, with the result that the stalks can be pushed over and damaged. If, on the other hand, the ground speed is less than it should be for a given auger rotational speed, the auger(s) will pull the stalks too fast along the slots, possibly ripping them out of the ground and damaging them. The known headers are accordingly speed-dependent.
The known headers are generally inefficient because a substantial quantity of trash material, for instance broken pieces of stalk, leaves and so forth, is fed into the threshing section of the combine harvester along with the crop ears. This in turn places a heavier burden on the combine harvester, resulting in increased fuel consumption and accelerated wear and tear than would be the case if the header were better able to separate trash from the ears.
The forwardly tapered gathering shoes of the known headers are frequently unable to get beneath and lift up crop material which has fallen down or been flattened and is lying prone in the field. This means that this material is not processed by the header and is accordingly wasted.
According to a first aspect of the invention there is provided a header for a harvesting machine, especially a combine harvester, comprising:
a plurality of laterally equispaced, side by side, rotatable augers extending in a forward direction, each auger having a rotatable auger shaft which is included upwardly towards the rear and an auger flight on the shaft,
correspondingly inclined troughs located beneath each auger with the auger flight being rotatable in the trough,
correspondingly inclined slots extending rearwardly from respective slot entrances at the forward end of the header, the slots being sufficiently wide to allow passage of stalks of material to be harvested but too narrow to allow passage of crop ears or other material to be collected so that the crop ears or other material to be collected can be stripped from the stalks by the action of the slot during forward movement of the header,
drive means for rotating the augers,
whereby
the slots are defined between the adjacent troughs and located substantially midway between adjacent auger shafts, and
the lower portion of an auger flight is rotatable in the lower portion of the trough and an upper part of an auger flight is exposed above the trough.
According to a second aspect of the invention there is provided a header for a harvesting machine, especially a combine harvester, comprising:
a plurality of laterally equispaced, side by side, rotatable augers extending in a forward direction, each auger having a rotatable auger shaft which is inclined upwardly towards the rear and an auger flight on the shaft,
correspondingly inclined troughs located beneath each auger with the auger flight being rotatable in the trough,
correspondingly inclined slots extending rearwardly from respective slot entrances at the forward end of the header, the slots being sufficiently wide to allow passage of stalks of material to be harvested but too narrow to allow passage of crop ears or other material to be collected so that the crop ears or other material to be collected can be stripped from the stalks by the action of the slots during forward movement of the header,
drive means for rotating the augers
wherein the measures of the augers, troughs and other elements of the header are chosen in a way that the distance between two slots is 50 cm as a maximum.
Conventionally, the distance between two slots is approximately 30 cm.
Preferably, there is no transverse overlap between auger flights of adjacent augers.
A transverse gap is typically provided between the auger flights of adjacent augers.
Slots are usually defined between inclined side edges of the troughs which are at the same or a lower elevation than the auger shafts. These slots are typically at a higher elevation than the bases of the troughs.
Typically, the maximum transverse dimension of an auger flight is slightly greater than the width of a trough, whereby the auger flight extends a small distance over the slots on either side.
Preferably, the plurality of augers defines a substantially inclined separation and transportation zone for the crop to be harvested.
The augers may be positioned sufficiently close together to convey relatively light and elongate trash material sideways at a relatively high level on top of the augers while the stripped crop ears are conveyed rearwardly in the troughs at a relatively low level.
Preferably, there is no separating wall between adjacent augers and no cover plates covering augers or gaps between augers either fully or partially.
The augers usually extend to auger tips defining the foremost end of the header, and auger flights extend to the auger tips.
According to a third aspect of the invention there is provided a method of harvesting crop ears from a standing stalk crop using a header which comprises a plurality of side by side, inclined, rotatable augers located above correspondingly inclined troughs which define correspondingly inclined slots between them, the method comprising the steps of:
moving the header in a forward direction through the standing stalk crop so that stalks of the crop are received in the slots, whereby crop ears can be stripped from the stalks by the action of the slots to fall into the troughs, and
rotating the augers to convey the stripped crop ears rearwardly in the troughs at a relatively low level and to convey relatively elongate and light trash material sideways on top of the augers.
Typically, the method includes the step of making use of a header comprising more slots per working width of the header than rows of stalk crop to be harvested from a corresponding width.
According to a fourth aspect of the invention there is provided a header for a combine harvester comprising:
a plurality of laterally equispaced troughs inclined upwardly in a rearward direction,
a first group of correspondingly inclined augers each located over a trough and having an auger shaft supporting a spiral auger flight, upper portions of the flights of the augers in the first group being exposed above the troughs for cooperation with one another,
a second group of correspondingly inclined augers located alongside the the first group of augers, each auger in the second group being located over a trough and having an auger shaft supporting a spiral auger flight of opposite hand to the auger flights of the augers in the first group, upper portions of the flights of the augers in the second group being exposed above the troughs for cooperation with one another,
means for rotating the first and second groups of augers in opposite rotational directions, and
correspondingly inclined slots defined between the upper edges of adjacent troughs, the slots being located midway between adjacent auger shafts at a level above the bases of the troughs, the slots extending rearwardly from respective slot entrances at the forward end of the header, such that when the header moves forwardly through a land planted with a stalk crop carrying crop ears which are to be processed by the combine harvester, the stalks of the crop enter the slots through the slot entrances and move rearwardly along the slots, the slots being sufficiently wide to allow passage of the stalks but too narrow to allow passage of the crop ears, whereby passage of the stalks through the slots causes crop ears to be stripped from the stalks to fall into the troughs to be conveyed rearwardly therein by the augers.